This invention has as its object to provide an image processing apparatus, which can obviate the need for image re-input, can effectively generate encoded data that falls within a set size, and can minimize deterioration of image quality. To this end, an image processing apparatus according to this invention includes first discrimination unit for discriminating the type of image of each of a plurality of regions, which form image data input, second discrimination unit for discriminating if the image data is inputted by a continuous scan of images, selection unit for selecting an encoding method used in compression of each region on the basis of discrimination results of the first and second discrimination unit, first compression unit for compressing image data of each region using the encoding method selected by the selection unit, and second compression unit for compressing information that pertains to the type of image of each region.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image processing apparatus comprising: input means for inputting image data; first discrimination means for discriminating a type of image of each of a plurality of regions, which form image data input by said input means; second discrimination means for discriminating if the image data is inputted by a continuous scan of images; selection means for selecting an encoding method used in compression of each region on the basis of discrimination results of said first and second discrimination means; and compression means for compressing image data of each region using the encoding method selected by said selection means, wherein said selection means selects a first encoding method if the type of image is a first type, regardless of whether or not the image data is inputted by the continuous scan of images, wherein said selection means selects a second encoding method if the type of image is a second type and the image data is inputted by a single scan of images, wherein said selection means selects a third encoding method if the type of image is the second type and the image data is inputted by the continuous scan of images, and wherein a compression ratio of the first encoding method is higher than a compression ratio of the second and third encoding methods and the compression ratio of the third encoding method is higher than the compression ratio of the second encoding method.
2. The apparatus according to claim 1 , wherein the first type is a natural image and the second type is a non-natural image.
3. The apparatus according to claim 2 , wherein the non-natural image is an artificial image represented by text, a thin line, a print halftone dot screen, or computer graphics, and the natural image is a photo image region.
4. The apparatus according to claim 2 , wherein each region is a unit of encoding, which consists of a plurality of pixels, said first discrimination means discriminates one of a plurality of types of images to which each of the plurality of pixels that form the region belongs, executes a statistical process of the pixels for each region, and discriminates a type of image to which the region belongs on the basis of a statistical value obtained by the statistical process.
5. The apparatus according to claim 4 , wherein information that pertains to the type of image of each region is attribute information for each region, which indicates a type to which that region belongs.
6. The apparatus according to claim 4 , wherein information that pertains to the type of image of each region is attribute information for each pixel, which indicates a type to which that pixel belongs.
7. The apparatus according to claim 4 , wherein information that pertains to the type of image of each region is code information which indicates the encoding method selected by said selection means.
8. The apparatus according to claim 4 , wherein the statistical process calculates the numbers of pixels that belong to respective types of the plurality of pixels which form the region, and when the number of pixels which belong to a predetermined type exceeds a predetermined threshold value, said first discrimination means determines that the region is a region of that predetermined type.
9. The apparatus according to claim 1 , wherein the selection of an encoding method is a selection of encoding coefficients used upon compressing the image data.
10. The apparatus according to claim 9 , wherein the encoding coefficients are a quantization matrix used upon compressing the image data.
11. The apparatus according to claim 1 , wherein said compression means is first compression means, and further comprising second compression means for compressing information that pertains to the type of image of each region and forming means for forming a data structure which includes at least first compressed data obtained by said first compression means, and second compressed data obtained by said second compression means.
12. The apparatus according to claim 11 , wherein said forming means inserts the second compressed data obtained by said second compression means in a header field of the first compressed data obtained by said compression means.
13. The apparatus according to claim 1 , wherein said input means can input image data which is continuously read by an automatic reader that can automatically read a document to be read.
14. The apparatus according to claim 1 , wherein said second discrimination means discriminates to see if an automatic reader is used.
15. The apparatus according to claim 1 , wherein said second discrimination means discriminates based on the number of images that have been continuously read.
16. The apparatus according to claim 1 , wherein said second discrimination means discriminates by comparing the number of images that have been continuously read with storage means for storing the image data.
17. The apparatus according to claim 2 , wherein said input means comprises a page description language rendering unit for generating image data by interpreting a page description language command described in a page description language, and said first discrimination means discriminates based on the page description language command interpreted by said page description language rendering unit if each region is a non-natural image region.
18. The apparatus according to claim 17 , wherein said first discrimination means determines a region formed of character pixels, vector pixels, or graphic pixels to be the non-natural image region on the basis of the type of page description language command.
19. The apparatus according to claim 1 , wherein said compression means is first compression means, and further comprising second compression means for compressing information that pertains to the type of image of each region, wherein said first compression means compresses the region using discrete cosine transformation, and said second compression means compresses the information that pertains to the type of region using runlength encoding.
20. The apparatus according to claim 11 , further comprising transmission means for transmitting the data structure formed by said forming means.
21. The apparatus according to claim 20 , wherein said transmission means is an interface used to connect a wireless or wired line.
22. An image processing method comprising: an input step of inputting image data; a first discrimination step of discriminating a type of image of each of a plurality of regions, which form image data input in said input step; a second discrimination step of discriminating if the image data is inputted by a continuous scan of images; a selection step of selecting an encoding method used in compression of each region on the basis of discrimination results in said first and second discrimination steps; and a compression step of compressing image data of each region using the encoding method selected in said selection step, wherein a first encoding method is selected in said selection step if the type of image is a first type, regardless of whether or not the image data is inputted by the continuous scan of images, wherein a second encoding method is selected in said selection step if the type of image is a second type and the image data is inputted by a single scan of images, wherein a third encoding method is selected in said selection step if the type of image is the second type and the image data is inputted by the continuous scan of images, and wherein a compression ratio of the first encoding method is higher than a compression ratio of the second and third encoding methods and the compression ratio of the third encoding method is higher than the compression ratio of the second encoding method.
23. A computer readable storage medium storing a computer program for making a computer implement an image processing method of claim 22 .
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
November 4, 2002
March 20, 2007
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